A Model Predictive Repetitive Process Control Formulation for Additive Manufacturing Processes

2015 ◽  
Author(s):  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers
Keyword(s):  
Additive Manufacturing ◽  
Process Control ◽  
Predictive Control ◽  
Reference Signal ◽  
Deposition Process ◽  
Open Loop ◽  
Two Dimensions ◽  
Manufacturing Processes ◽  
Layer By Layer ◽  
Repetitive Process

Additive Manufacturing (AM) processes are a class of manufacturing processes in which parts are fabricated in a layer-by-layer fashion. The layer-by-layer fabrication method creates layer-to-layer dynamics. Implementing process control that neglects the layer-to-layer dynamics can lead to process instability. While repetitive process controllers which utilize only layer-to-layer feedback are a viable method, their usefulness is limited in that they are not well-suited for tracking non-periodic layer-domain references. However, since the entire reference signal is typically known a priori in AM process fabrications, a predictive control methodology can be useful for controlling fabrications in which the reference signal is non-periodic. In this paper a model predictive control formulation is extended to two-dimensions and utilized for repetitive process control Simulation results comparing open-loop and controlled fabrications for a Laser Metal Deposition process are given.

Repetitive Process Control of Laser Metal Deposition

2014 ◽  
Author(s):  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers
Keyword(s):  
Process Control ◽  
Dynamic Models ◽  
Open Loop ◽  
Metal Deposition ◽  
Hammerstein Model ◽  
Layer By Layer ◽  
Laser Metal Deposition ◽  
Material Source ◽  
Stabilizing Controller ◽  
Repetitive Process

The Laser Metal Deposition (LMD) process is an additive manufacturing process in which a laser and a powdered material source are used to build functional metal parts in a layer by layer fashion. While the process is usually modeled by purely temporal dynamic models, the process is more aptly described as a repetitive process with two sets of dynamic processes: one that evolves in position within the layer and one that evolves in part layer. Therefore, to properly control the LMD process, it is advantageous to use a model of the LMD process that captures the dominant two dimensional phenomena and to address the two-dimensionality in process control. Using an identified spatial-domain Hammerstein model of the LMD process, the open loop process stability is examined. Then, a stabilizing controller is designed using error feedback in the layer domain.

scholarly journals Repetitive Process Control of Additive Manufacturing With Application to Laser Metal Deposition

2019 ◽  
Vol 27 (2) ◽  
pp. 566-575 ◽  
Author(s):  
Patrick M. Sammons ◽  
Michelle L. Gegel ◽  
Douglas A. Bristow ◽  
Robert G. Landers
Keyword(s):  
Additive Manufacturing ◽  
Process Control ◽  
Metal Deposition ◽  
Laser Metal Deposition ◽  
Repetitive Process

scholarly journals Analysis and characterization of additive manufacturing processes

2021 ◽  
Vol 13 (4) ◽  
pp. 167-180
Author(s):  
Andra TOFAN-NEGRU ◽  
Cristian BARBU ◽  
Amado STEFAN ◽  
Ioana-Carmen BOGLIS
Keyword(s):  
Additive Manufacturing ◽  
Complex Geometry ◽  
Cutting Tools ◽  
Manufacturing Processes ◽  
Layer By Layer ◽  
Advantages And Disadvantages ◽  
Finishing Processes ◽  
Short Time ◽  
Physical Phenomena ◽  
Am Processes

Recently, additive manufacturing (AM) processes have expanded rapidly in various fields of the industry because they offer design freedom, involve layer-by-layer construction from a computerized 3D model (minimizing material consumption), and allow the manufacture of parts with complex geometry (thus offering the possibility of producing custom parts). Also, they provide the advantage of a short time to make the final parts, do not involve the need for auxiliary resources (cutting tools, lighting fixtures or coolants) and have a low impact on the environment. However, the aspects that make these technologies not yet widely used in industry are poor surface quality of parts, uncertainty about the mechanical properties of products and low productivity. Research on the physical phenomena associated with additive manufacturing processes is necessary for proper control of the phenomena of melting, solidification, vaporization and heat transfer. This paper addresses the relevant additive manufacturing processes and their applications and analyzes the advantages and disadvantages of AM processes compared to conventional production processes. For the aerospace industry, these technologies offer possibilities for manufacturing lighter structures to reduce weight, but improvements in precision must be sought to eliminate the need for finishing processes.

Multiphysics Challenges for Controlling Layered Manufacturing Processes Targeting Thermomechanical Performance

2014 ◽  
Author(s):  
John G. Michopoulos ◽  
Samuel Lambrakos ◽  
Athanasios Iliopoulos
Keyword(s):  
Additive Manufacturing ◽  
Process Control ◽  
Modeling And Simulation ◽  
Functional Performance ◽  
Modeling Processes ◽  
Layered Manufacturing ◽  
Simple Problem ◽  
Manufacturing Processes ◽  
On Demand ◽  
Mass And Heat Transfer

In an effort to enable on-demand process control of additive manufacturing processes for achieving component performance by design from a modeling and simulation perspective and context, we introduce a method for identifying relevant modeling and simulation challenges for the purpose of motivating research that addresses this problem. We first present the abstraction of the multiscale modeling processes connecting process control with functional performance both from the forward and inverse perspectives. We subsequently introduce a brief ontology describing the ordering of dependency and membership of all components of a model in order to isolate the potential areas where challenges can be exposed. We subsequently select some features that are usually ignored by the community during modeling. In particular, we demonstrate using a simple problem of mass and heat transfer, which is relevant to layered additive manufacturing, the implications and dangers related to ignoring process dependence on deposition path history.

Statistical Process Control Based Supervisory Generalized Predictive Control of Thin Film Deposition Processes

2004 ◽  
Vol 128 (1) ◽  
pp. 315-325 ◽  
Author(s):  
Jionghua Jin ◽  
Huairui Guo ◽  
Shiyu Zhou
Keyword(s):  
Thin Film ◽  
Process Control ◽  
Statistical Process Control ◽  
Predictive Control ◽  
Thin Film Deposition ◽  
Deposition Process ◽  
Film Deposition ◽  
Generalized Predictive Control ◽  
Statistical Process ◽  
Production Run

This paper presents a supervisory generalized predictive control (GPC) by combining GPC with statistical process control (SPC) for the control of the thin film deposition process. In the supervised GPC, the deposition process is described as an ARMAX model for each production run and GPC is applied to the in situ thickness-sensing data for thickness control. Supervisory strategies, developed from SPC techniques, are used to monitor process changes and estimate the disturbance magnitudes during production. Based on the SPC monitoring results, different supervisory strategies are used to revise the disturbance models and the control law in the GPC to achieve a satisfactory control performance. A case study is provided to demonstrate the developed methodology.

Additive Manufacturing of Titanium Parts Using 3D Plasma Metal Deposition

2018 ◽  
Vol 941 ◽  
pp. 2137-2141 ◽  
Author(s):  
Kevin Hoefer ◽  
Peter Mayr
Keyword(s):  
Additive Manufacturing ◽  
Raw Materials ◽  
Deposition Process ◽  
Metal Deposition ◽  
Utilization Efficiency ◽  
Layer By Layer ◽  
Metallic Structures ◽  
Additional Advantage ◽  
Production Technologies ◽  
Material Utilization

Additive manufacturing of titanium components offers several advantages compared to conventional production technologies such as higher material utilization efficiency and increased geometric possibilities. In comparison to laser powder bed processes, arc-based additive manufacturing processes have the additional advantage of an almost unlimited assembly space, higher deposition rates and an improved utilisation factor of raw materials. Disadvantages of wire-based methods are the restricted availability of different types of wire consumables, the fact that the wire feed rate is directly coupled to the heat input and the lack of possibility to create multi-material structures in-situ.Within this work, the 3D Plasma Metal Deposition (3DPMD) method, based on a plasma powder deposition process is introduced. 3DPMD has some special advantages compared to the established plasma powder process and other additive processes. For example, up to four powders, which can differ in terms of material and powder fraction, can be mixed within one layer. This allows a targeted adaption of local properties (microstructure, mechanical properties, wear resistance, porosity, etc.) to the targeted load type and level. The tailored introduction of reinforcement particles, e.g. tungsten or titanium carbides, into the component is a simple example.The study aims to demonstrate the suitability of the 3DPMD for the production of titanium components in layer-by-layer design. Various demonstrators are prepared and analysed. The microstructures, the porosity and the hardness values of the different structures are analysed.In summary, 3DPMD offers the possibility to produce titanium structures with and without reinforcement particles. Using automated routines, it is possible to generate metallic structures directly from the CAD drawings using welding robots. Microstructures and properties are directly related to the process and, therefore, structure-process-property relationships are discussed within this work.

scholarly journals Robust Additive Manufacturing Performance through a Control Oriented Digital Twin

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 708
Author(s):  
Panagiotis Stavropoulos ◽  
Alexios Papacharalampopoulos ◽  
Christos K. Michail ◽  
George Chryssolouris
Keyword(s):  
Additive Manufacturing ◽  
Process Control ◽  
Design Method ◽  
Control Design ◽  
Open Loop ◽  
Linear Matrix ◽  
Loop Model ◽  
Digital Twin ◽  
Manufacturing Process Control ◽  
Robust Control Design

The additive manufacturing process control utilizing digital twins is an emerging issue. However, robustness in process performance is still an open aspect, due to uncertainties, e.g., in material properties. To this end, in this work, a digital twin offering uncertainty management and robust process control is designed and implemented. As a process control design method, the Linear Matrix Inequalities are adopted. Within specific uncertainty limits, the performance of the process is proven to be acceptably constant, thus achieving robust additive manufacturing. Variations of the control law are also investigated, in order for the applicability of the control to be demonstrated in different machine architectures. The comparison of proposed controllers is done against a fine-tuned conventional proportional–integral–derivative (PID) and the initial open-loop model for metals manufacturing. As expected, the robust control design achieved a 68% faster response in the settling time metric, while a well-calibrated PID only achieved 38% compared to the initial model.

scholarly journals Metal Additive Manufacturing by Powder Blown Beam Deposition Process

2019 ◽  
Vol 9 (2) ◽  
pp. 5291-5304
Keyword(s):  
Additive Manufacturing ◽  
Deposition Process ◽  
Functionally Graded ◽  
Metal Foil ◽  
Layer By Layer ◽  
Graded Materials ◽  
Available Technology ◽  
Materials Used ◽  
Testing Standards ◽  
Beam Deposition

Additive Manufacturing (AM) is a tool less manufacturing process for building complex components layer by layer. Powder based AM techniques are used for producing porous and dense parts or products by Powder Bed Fusion (PBF) and powder blown Beam Deposition (BD) processes respectively suitable for different applications. The present review is mainly focused on the commercially available technology of powder blown Beam Deposition (BD) process for producing fully dense parts, and functionally graded materials used in automotive, aerospace, defense, and nuclear reactors. The properties of BD parts and comparison of the properties of BD parts with Selective Laser Melting (SLM), casting, and Acram's Electron Beam Melting (EBM) parts are presented. This paper provides an insight into the microstructural characteristics and mechanical properties of parts produced by BD process. A brief discussion is presented on challenging issues and applications of BD process. An attempt is made to present available and under development AM testing standards used to evaluate the properties of AM parts. This review also focused on porous parts produced by BD process for medical applications, and metal foil based BD process. Here, new developments in AM process like hybrid manufacturing and 4D printing are also discussed

scholarly journals Investigation of Applicability of Additive Manufacturing Processes to Appropriate Technologies for Developing Countries

2021 ◽  
Vol 7 (2) ◽  
pp. 188-195
Author(s):  
Dong-Gyu Ahn
Keyword(s):  
Developing Countries ◽  
Additive Manufacturing ◽  
Industrial Revolution ◽  
Low Cost ◽  
Three Dimensional ◽  
Appropriate Technology ◽  
Manufacturing Processes ◽  
Layer By Layer ◽  
Layer Deposition ◽  
Am Processes

In recent years, additive manufacturing (AM) processes have emerged as an important manufacturing technology for a multi-item small sized production to lead the 4th industrial revolution. The layer-by-layer deposition characteristics of AM process can rapidly produce physical parts with three-dimensional geometry and desired functionality in a relatively low cost environment. The goal of this paper is to investigate the applicability of AM process to appropriate technologies for developing countries. Through the review of examples of appropriate technology of the AM process, the possibility of a practical usage of the AM process for the appropriate technologies is examined. In addition, significant applications of the AM process to the appropriate technology are introduced. Finally, future issues related to production of physical parts for developing countries using the AM process are discussed from the viewpoint of the appropriate technology.

Robot Assisted Additive Manufacturing of Thin Multifunctional Structures

2018 ◽  
Author(s):  
Prahar M. Bhatt ◽  
Max Peralta ◽  
Hugh A. Bruck ◽  
Satyandra K. Gupta
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing System ◽  
Robotic Manipulator ◽  
Manufacturing Processes ◽  
Layer By Layer ◽  
Robot Assisted ◽  
Manufacturing Operations ◽  
Multiple Materials

Thin multifunctional structures need to be composed from many different materials. Currently, very few additive manufacturing processes are capable of working with multiple materials. Additive manufacturing processes that work with multiple different materials pose significant constraints on material options. This significantly limits the kind of multifunctional structures that can be produced using additive manufacturing. A robot assisted sheet lamination based additive manufacturing system is developed in this paper. The system utilizes a 6-DOF robotic manipulator to perform the manufacturing operations such as cutting, assembly, tape-layup, and bonding to build the part layer by layer. A flexible ornithopter wing have been built using the proposed system. We have characterized the system in terms of part performance as well as automation efficiency.

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